504 BRAINARD ANI> SEELY — THE CALCIPEROUS FORMATION. 



The pure rock just above the middle of the division carries the fossil 

 Orthoceras primogenium, Vanuxem. It also contains those remarkable hem- 

 ispherical, banded masses which have hern described as concretions, but 



which are now known to he of organic origin. These masses res! upon a 

 layer of oolite. They were described by Dr. J. II. Steel*in 1825, with a 

 figure illustrating them. Mather, in his report on the first geological dis- 

 trict of New York, copied both text and illustration, ami in a foot-note 

 added: " Some of the round masses described as concretions analogous t" 

 oolites are organic and will he described in the paleontological report. 

 The form found in Shoreham, Vermont, is hemispherical, from six to twenty 

 indies in diameter, handed from the center outward like agate, and with a 

 tinge of purple color. Microscopic sections show the Bpongy structure of the 

 calciferoua Bponges, irregular canal- penetrating the granular mass. Thia 

 form may belong to the Cryptozoon of Hall; J it is, however, probably 

 different specifically from the Saratoga fossil, and from the earliest known 

 observer it may he appropriately named Cryptozoon steeli. 



The rock in cliffs looks like a wall of white marble. Reticulations of 

 dolomite appear on the weathered surface. The thickness of division //is 



295 feet. 



Division is sharply separated from B below by a peculiar fine-grained 

 sandstone containing some calcareous matter. The weathered portions 

 resemble fine-grained wood, ami some layers are pin-holed with worm 

 burrows, Scolithua minutus, according to Wing. Upon this sandstone lies 

 magnesian limestone in beds weathering drab, and this is followed by Band- 

 stone, sometimes almost like quartzite, but usually calciferoua or dolomitic. 

 Above this, and the highest of the division, is a magnesiau limestone frequently 

 cherty. The whole division is made up of alternations of sandstone ami 

 magnesian limestone. 



A few obscure undescribed specie- of gasteropods ami cephalopoda are 

 found in division < ', in addition to the numerous worm burrows at the very 

 bottom. The thickness is 350 feet. 



Division h may be briefly described aa to it- lithology. It has at its base 

 blue limestone in beda one or two feet thick, often with maguesian limestone 

 aa well aa Bandy limestone, the latter weathering to a ferruginous granular 



mass. Drab and brown magnesian limest follows, which contains also, 



toward the middle, several beds of tough saudstone. Then comes Bandy 

 limestone in thin beds, weathering on the edges in horizontal ridges one or 

 two inches apart, giving the escarpment b peculiar, handed appearance. 

 Blue limestonea appear above in thin beda separated from each other by very 

 thin, tough, slaty layers, winch protrude on the weathered edges in undulat- 



'.in. Jour. Science, l-i Sei . Vol. I \, pp 16 19 

 ■ "wn fork. 1842, pp n i 



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